Recognise this?

Tim its an old fashioned mangol worsel, they had a number of different varieties, some were round and just that colour and some were long just like the one you have. If we had a field full of that sized mangol's we would be very disapointed, should be double or treble that size.
A good winter feed for an old cow, not a lot of flavour, raw or cooked, very high water content, protect it from the frost. Its a bianual and seeds / bolts like a sugar beet.
Father stopped growing mangols when he started to grow sugar beet as the beet tops were fed to the cows instead, and silge was just starting to become popular in the 1940's/50's

Thanks Fred. I've heard the name, but haven't come across anyone growing them for years. When I was a kid, I used to help out an old-fashioned farmer who still grew them to feed to his cattle (this was in the 1980s) but haven't seen one since!

As the owner of the said vegetable, I'm very upset that its the food for an 'old cow'. I may be very pregnant at the moment, and moving around like an old bovine, but...:)

Hannah,
I haven't tried it yet (can humans eat them?) but Fred mentions they haven't got a lot of flavour, so we won't make you eat it!

I've just been told by Nick that it's a variety of radish called a 'French Breakfast'. He's adamant that's what it is!
http://en.wikipedia.org/wiki/Radish

Listen, so far I'm the only one who's tried it and I can confirm it is an overgrown and over-mature French Breakfast radish.
How do I know?
Well it's more peppery than the Lonely Hearts Club Band which means in agronomist speak that it contains lots of glucosinolates - the things that oilseed rape breeders try to avoid because it taints the cake from oil extraction and makes it unpalatable to cattle. Hence why it's not a mangle wurzel - cows wouldn't go near it.
The reason for my unhealthy interest in this? A year working for a veg seed breeder in NZ turned me into a complete brassica-bore. If you're having trouble sleeping I can go on....
PS - Well done, Tim. You've had six comments on this post - that's got to be a P.B. hasn't it? Worryingly it means at least six people read your rambling drivel.
Oh no, it's alright - I see three of the comments are your own!

Nick,
Thanks for contributing to the debate. I imagine you're very popular at dinner parties!
It also has to be a pb for you - getting a whole five paragraphs into an email before you become cynical and sarcastic!
Thanks, as well, for (including this response) getting me up to seven comments!

Not sure what sort of vegetable it is. It's certainly quite strange looking - I've never seen a vegetable wearing glasses before

look in your seed catalouge under china rose winter radish, bet its hot and tough because of size.

Is it a sweet potato?